1. Field of the Invention
The present invention relates to a method and apparatus of recording a high definition digital television (HDTV) broadcast signal to a high-density disk storage medium such as a HD-DVD (High-Density Digital Versatile Disk).
2. Description of the Related Art
A conventional analog television signal is transmitted through air or cable after AM or FM modulation.
In these days, digital technologies related with video compression and modulation/demodulation has been remarkably advanced, so that digital television broadcast, whose standard is locally under discussion, is being introduced in air broadcasting system. The digital television broadcast system has adopted MPEG standard as video and audio compression method.
The digital broadcast system can provide higher quality than analog system, transmit several different programs through an allocated single band, and make it possible to fully use resources and media for digital communication and storage.
In digital broadcasting system, several programs whose data are encoded to MPEG are multiplexed and then delivered in the format of TS (Transport Stream) to a receiving terminal such as a STB (Set Top Box). The receiving terminal extracts the TS carrying a selected program from received data and decodes the extracted TS into original audio and video signal which are applied to a displaying apparatus such as a television set.
FIG. 1 depicts a digital broadcast receiving system schematically. This system consists of a STB 100, a streamer 200, IEEE 1394 communication line, and a conventional television set 300. In the STB 100, a receiving unit 11 receives digital television broadcast signal, which includes encoded several programs, and extracts TS carrying a desirable program selected by a controller 14 according to user's command. The extracted TS is decoded into video and audio signal by a TS decoder 12 and then outputted to a television set 300. Otherwise, the extracted TS is delivered to the streamer 200 through IEEE 1394 interfaces 13 and 21 to record the selected program to a disk storage medium 23.
The STB 100 can also receive TS-formatted program recorded in the disk storage medium 23 from the streamer 200 through the IEEE 1394 interfaces 13 and 21, and decode the received TS to video and audio signal through the TS decoder 12. The decoded video and audio signal are outputted to the television set 300.
In the meantime, a high-density DVD (Digital Versatile Disk) is being developed to record high-quality moving pictures of high definition grade since a digital television set being able to present an HDTV signal is being commercialized. The storage capacity target of a high-density DVD is about 15 Gbytes which is 3.2 times of about 4.7 Gbytes of a conventional DVD. It is possible to record in a high-density DVD about 135 minute-long moving picture data of high definition grade.
Therefore, a standard for recording an HDTV signal broadcasted from a broadcasting station to a writable high-density DVD through a STB and a streamer as aforementioned is under discussion among related companies.
However, a provisional standard for a streamer specifies that acceptable maximum input bit rate is about 11.0 Mbps whereas the data bit rate of moving pictures of high definition grade has a range of 19.26˜23 Mbps. As a result, a streamer observing the provisional standard can not record high definition moving pictures broadcasted from a broadcasting station to a disk recording medium normally. Therefore, a new recording method for an HDTV signal is needed.
In addition, if an HDTV signal is widely used in the near future, there will be great need of receiving HDTV program directly without an intermediary STB and recording it.